Hydraulic jack assemblage



IN V EN TOR.

July 24, 1962 w. L. COLGAN HYDRAULIC JACK ASSEMBLAGE Filed D60. 19, 1960 WILLIAM L.COL GAN mm: m

ATTORNEYS.

United States Patent 3,045,653 HYDRAULIC JACK ASSEMBLAGE William L. 'Colgan, West Allis, Wis., assignor to Applied Power Industries, Inc., a corporation of WlSCODSlIl Filed Dec. 19, 1960, Ser, No. 76,595

Claims. (Cl. 121-46) movement of which is controllable with the aid of an oscillatory frame transporting handle, in garages or the like in order to lift vehicles while work is being performed thereon. These prior service jacks were usually provided with hydraulic systems including a pump for applying hydraulic pressure to the ram plunger in order to lift a load and a release valve operable from the swinging end of the handle to lower the load by permitting pressure liquid to escape from the ram to a reservoir. Some of these prior jack assemblages were also provided with relief valves for preventing excessive pressure from being produced in the ram, but these prior jack units were relatively complicated and subject to frequent repair due to the lack of proper safety devices while also requiring separate valves and control mechanism for releasing and relieving the hydraulic pressure.

' It is therefore an important object of the present invention to provide a simplified and more durable control system for such service jacks whereby the flexibility and safety thereof are enhanced.

Another important object of this invention is to provide an improved portable hydraulic jack unit wherein the normally functioning release valve also serves as a relief valve under certain conditions of operation.

.A further important object of the invention is to provide an improved release valve assemblage for jacks embodying 1a pivoted load moving lever and a pivoted handle for controlling the movement of the lever, and wherein a common release valve serves to limit the movement of the lever to a predetermined distance of travel and to also protect the unit against damage due to development of excessive hydraulic pressure. I

Still another important object of the present invention is to provide improved mechanism for hydraulic rams, comprising a bell crank cooperating with a combined release and relief control valve to perform the triple function of either automatically releasing the ram actuating hydraulic pressure to arrest the movement of the ram plunger, or to automatically unload the ram from abnor mal or excessive pressure, or to effect manual withdrawal of the lifting lever from the load. 1 These and other more specific objects of the invention will be apparent from the following description.

A clear conception of the features constituting the present, improvements, and of the construction and operation ofa typical hydraulic service jack embodying the invention, may be had by referring to the drawing accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the various views. V

FIGURE 1 is vertical section taken along an irregular line through a portable hydraulic service jack, showing the Patented July 24, 1962 ice load lifting lever lowered in solid lines and elevated in dot-and-dash lines, and also showing the manipulating handle lowered;

FIGURE 2 is a part sectional top view of the same service jack, the section having been taken centrally and longitudinally through the manipulating handle; and

FIGURE 3 is a diagram of the improved valve control and manipulating system constituting the present invention.

While the invention has been shown and described herein as having been embodied in only one specific type of service jack, it is not intended to thereby restrict its use to this particular type of jack; and it is also contemplated that descriptive terms employed herein be given the broadest possible interpretation consistent with the disclosure.

Generally defined, applicants invention is applicable to a jack assemblage having a load lifting lever and a hydraulic-pressure, actuated ram for moving the lever, together with a 'valve for effecting escape of pressure liquid from the ram either when the hydraulic pressure within the ram reaches an abnormal-1y high and dangerous value, or

when the load lifting lever has attained the limit of its lifting stroke, or whenever it is desired to retract or withdraw the lever from load engaging or lifting position.

Referring to the drawing, the portable hydraulic service jack shown therein comprises in general, an elongated main frame 5 having transporting wheels 6 at one end and a hollow manipulating handle 7 pivotally attached to its opposite end; a load lifting lever 8.pivotally secured to a medial portion of the frame 5 and having a load engaging saddle 9 mounted upon the swinging lever end; a hydraulic ram having power cylinder 10 supported by the frame 5 between the handle 7 and the lever 8 and having therein a reciprocable plunger 11 pivotally attached to said lever and which is movable in one direction by pressure liquid to elevate the saddle 9 while being movable in the opposite direction to lower this saddle by means of a pair of helical tension springs 12; a pump 13 operable by oscillation of the handle 7 to deliver liquid under pressure from a supply reservoir 14 past suitable valves (not shown) into the plunger displacement chamber of the cylinder 10 to elevate the saddle 9; and a release valve 15 operable by an actuating knob 16 at the swinging end of the handle 7 to effect return of liquid from within the power cylinder 10 to the reservoir 14 under the influence of the springs 12.

All of the foregoing service jack structure except the release valve is well known and the present invention relates primarily to' improved mechanism for effecting functioning of the release valve 15 under different operating conditions.

This improved valve actuating mechanism comprises in general a composite'lever or bell crank 18 having a fixed supporting pivot 19 and three integral arms 20, 21, 22 of which the arm 20 is cooperable directly with the release valve 15 to open the same. This valve 15 is also adapted to be opened by a rod 23 extending through the hollow handle 7 and having its outer end provided withscrew threads 24 coacting with internal threads in the knob 16 while its opposite 'end engages the frustro conical side of a rotary motion transmitting element 25 the opposite flat side of which is'engageable with the swinging end of the bell crank arm 21. The valve 15 is additionally adapted to be opened by an elongated link 26 one end of which is attached either to the lever 8 remote from its pivot 27 as in FIGURE 1 or directly to the ram plunger 11 as inFIGURE 3 while its opposite end extends loosely through the swinging end of the bell crank arm. 22 and is provided with a collar 28 adapted to engage this arm.

This release valve actuating knob 16 is rotatable relative to the manipulating handle 7 but is fixed against axial movement so that rotation of this knob will move the rod 23 longitudinally in either direction depending upon the direction of rotation of the knob 16. The motion transmitting element 25 has a central shaft 30 rotatably mounted in a bore formed in one of the pivots 31 for the handle 7, and this shaft 30 is also slidable along its bore in one direction by the longitudinal movement of the rod 23 hearing against its frustro-conical surface. Thus, when the rod 23 is moved longitudinally toward its pivots, 31, it will press against the tapered surface of the element 25 and will move this element axially so as to swing the bell crank 18 in a counter-clockwise direction as viewed in FIGURE 3 thereby causing the bell crank arm 20 to open the valve 15, and the frustro-conical shape of the element surface enables the rod 23 to function regardless of the angular position of the handle 7 relative to its pivots 31.

The release valve 15 which is adapted to connect the displacement chamber of the ram cylinder with the liquid reservoir 14, may be of the axially movable metering needle or ball type and is normally urged toward closed position by a spring 33 as shown in FIGURE 3, and this valve has a stem 34 which passes loosely through an opening in the bell crank arm and is provided Withan abutment disk 35. The helical spring 33 should, of course, be of sufficient strength to hold the valve 15 closed against normal hydraulic pressure existing within the ram, but adapted to permit this release valve to open automatically when this pressure rises abnormally. The cylinder 10 of the ram is also pivotally suspended to swing about a pivot 37 in order to compensate for the swinging motion of the load lifting lever, see FIGURE 1.

When the service jack has been constructed and assembled as above described, and the various parts have been properly adjusted, its operation is as follows. With the lever 8 lowered as in FIGURES l and 3, the handle 7 may be utilized to transport the unit from place to place and to position the saddle 9 beneath the load which is to be lifted, whereupon the handle 7 may be oscillated about its pivots 31 to operate the hydraulic pump and to raise the saddle into engagement with the load in a well known manner. If at any time the lever 8 or the saddle 9 encounters an immovable obstruction and the pumping operation continues, the hydraulic pressure within the ram may rise to such an extent that parts of the ram are subjected to dangerous abnormal pressure, but under these conditions the valve 15 will open automatically against the pressure exerted by the spring 33 to release such pressures.

Then too, if thepumping operation is continued after the lever 8 has reached its maximum elevated position there may be danger of breaking parts of the mechanism, and before such possibility arises the connection 26 and the collar 28 which are moved forward with the advancement of the ram plunger 11 will coact with the bell crank arm 22 to also automatically open the valve 15 and to release the hydraulic pressure from within the ram whenever the lever 8 has been fully elevated.

After the load lifting lever 8 has been elevated and in order tolower the same, it is only necessary to rotate the manipulating knob 16 at the swinging end of the handle in one direction so as to cause the screw threads 24 to move the rod 23 toward the pivots 31. This movement of the rod 23 will force the element 25 laterally against the bell crank arm 21 thereby swinging this bell crank about its pivot 19 and causing the arm 20 to open the valve 15. This manual opening of the valve 15 permits the springs 12 to retract the ram plunger 11 so as to lower the load lifting lever and to force the liquid from within the cylinder 10 into the reservoir 14, and such manipulation of the knob 16 may be effected regardless of the angular position of the handle 7 due to the frustro-conical formation of the element 25.

When the knob 16 is subsequently rotated in the opposite direction, the release valve spring 33 will close the valve 15 and will also press against the arm 20 of the bell crank 18 to swing this bell crank in a counter clockwise direction .as viewed in FIG. 3, thereby preventing lost motion between the element 25 and the adjacent crank arm 21 and end of the rod 23.

From the foregoing description it should be apparent that the present invention provides a simple but reliable hydraulic jack assemblage wherein the single valve 15 performs the triple function of unloading the ram when subjected to abnormal pressure, of arresting the movement of the lever 8 at the end of its stroke, and of effecting lowering or retraction of the load lifting lever. The improved motion transmitting mechanism for effecting manual actuation of the valve 15 enables the knob 16 to be manipulated with the handle 7 in any position, and the entire control system insures maximum safety of operation.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In a jack assemblage having a load lifting member and a hydraulicpressure-actuated ram for moving said member, a valve for controlling escape of pressure liquid from within said ram to lower said member, an oscillatory handle for effecting operation of said ram to move said member into load engaging position, a rod carried by and movable longitudinally of said handle, an element movable laterally of said handle and having a frustro-conical surface disposed in the path of movement of said rod and engaged thereby to effect such movement of said element, and means operable by said element upon lateral movement thereof for opening said valve to permit escape of liquid from said ram.

2. In a jack assemblage having a load lifting member and a hydraulic-pressure-actuated ram for moving said member, a valve for controlling escape of pressure liquid from within said ram to lower said member, an oscillatory handle for effecting operation of said ram to move said member into load engaging position, a rod carried by and movable longitudinally of said handle, an element mounted for sliding movement laterally of said handle and having a frustro-conical surface engaged by said rod for moving said element, and a bell crank engaged by said element for swinging movement upon lateral movement thereof when said rod is moved longitudinally for opening said valve to permit escape of liquid from said ram.

3. In a jack assemblage having a load lifting member and a hydraulic-pressure-actuated ram for moving said member, a valve for controlling escape of pressure liquid from within said ram to lower said member, an oscillatory handle for effecting operation of said ram to move said member into load engaging position, a rod carried by and movable longitudinally of said handle, means associated with the swinging end of said handle for moving said rod toward the opposite end of the handle, a rotary element mounted for movement laterally of the plane of oscillation of said handle and having a frustro-conical surface engageable by said rod to effect such movement of said element, and pivotally mounted means engaged by said element for operation upon lateral movement of said element for opening said-valve to permit escape of liquid from said ram.

4. In a jack assemblage having a load lifting member and a hydraulic-pressure-actuated ram for moving said member, a valve for controlling escape of pressure liquid from within said ram to lower said member, a handle for effecting operation of said ram to move said member into load engaging position, a rod carried by and movable longittudinally of said handle, means supported in proximity to said handle for moving said rod, an element movable laterally of the plane of movement of said rod and having a cam surface positioned in the path of movement of said rod and engageable thereby to efiect lateral movement of the element, and means engaged by said element and operable upon lateral movement thereof for opening said valve to permit escape of liquid from said ram.

mal hydraulic pressure, means operable by said ram and coasting with another of said arms to open said valve Whenever said lever has reached the limit of its load lifting position, and manually manipulable means coacting with the other of said arms to open said valve to effect retraction of said lever.

References Cited in the file of this patent UNITED STATES PATENTS Ferris Nov. 20,1928 Urton June 24, 1930 

